1. Field of the Invention
The present invention relates generally to an autonomous mobile robot, and in particular, to a home network system and method for an autonomous mobile robot to travel along the shortest travel route to a destination where a user is located and perform a corresponding operation set according to a user's instructions.
2. Description of the Prior Art
Generally, an autonomous mobile robot has power and a sensor mounted in a body and thus is capable of traveling autonomously without a signal and power supply from the external environment. The autonomous mobile robot is embedded with map information on a predetermined space for the autonomous travel in the predetermined space, the autonomous mobile robot finds its current location, sets a travel route to the destination, and moves to the set destination while avoiding obstacles sensed through the sensor.
Autonomous mobile robots have been developed as cleaner robots for cleaning an indoor space and as security robots for guarding an indoor space of a house from an external invader.
Typically, a conventional autonomous mobile robot comprises a traveling unit for incorporating movement of a body, a sensor units for sensing obstacles during moving, a controller for calculating and controlling a travel route of the autonomous mobile robot using data from the traveling unit and the sensor unit, and a power supply unit for charging and supplying power.
There are various types of traveling unit including a wheel type using a plurality of wheels rotated by a servomotor or a stepping motor, a caterpillar type using a caterpillar, or a joint type using a plurality of legs. However, generally a wheel type traveling unit is applied because it is controlled in a simple manner.
The sensor unit senses obstacles such as walls using an ultrasonic sensor or a laser sensor, and provides a resultant signal to the controller. A sensor applied to the sensor unit is typically installed at the front of the mobile robot for sensing obstacles in the traveling direction.
The controller has a microprocessor and a memory, and controls the general operation of the autonomous mobile robot, it transmits a movement command to the traveling unit, and controls the operation of the traveling unit to avoid the obstacles by a program mounted in the autonomous mobile robot according to a sensing signal provided from the sensor unit.
The power supply unit charges and provides power required for driving, operation and movement of the autonomous mobile robot, and enables the autonomous mobile robot to operate for a predetermined time duration according to the charge amount without the use of external power supply.
Generally, the movement to the destination by the autonomous mobile robot is made such that beacons are installed at fixed locations in the travel route and emit signals, and the autonomous mobile robot finds the location of the beacons using the intensity of received signals from the beacons, infers the beacon's location, and induces the movement of the mobile robot to the destination.
FIG. 1 is a view of a travel route mapping in a multi-sided space of a conventional autonomous mobile robot using beacons.
As illustrated in FIG. 1, the autonomous mobile robot starts at a starting point 3 in a room having a space 1 in which obstacles exist, travels while avoiding the obstacles by an obstacle recognizing sensor, and generates a route trace by an odometer.
At this time, the autonomous mobile robot receives signals from beacons 41 to 47 installed at specific points while moving around the indoor environment, and thereby obtains additional information of the indoor space.
Thereby, the autonomous mobile robot finds its relative location based on the route trace by the odometer and beacon signals received from the beacons 41 to 47, and thus maps a travel route 2 of the multi-sided space 1. That is, the autonomous mobile robot moves to the corresponding destination depending on the beacon signals received from the beacons 41 to 47. Although this is the shortest distance along which the autonomous mobile robot may travel to the corresponding destination, the travel route 2 disadvantageously involves unnecessary movement.
As an alternative movement method of the autonomous mobile robot, the autonomous mobile robot has a camera, and the autonomous mobile robot may process an image taken through the camera, find its location and thus map the travel route.
FIG. 2 is a flowchart illustrating a method for measuring the travel route of a conventional autonomous mobile robot using an image sensor.
As illustrated in FIG. 2, in step S11 when driving is selected, the autonomous mobile robot captures and stores images of the current floor space in step S12. In step S13, the autonomous mobile robot captures images while traveling around the floor and determines whether a predetermined time duration has elapsed in step S14. If a predetermined time duration has elapsed, the autonomous mobile robot captures an image of the floor space at the time, and in step S15 compares the image with the previous image.
The autonomous mobile robot measures the displacement of the image based on the image comparison result in step S16. Subsequently, in step S17 the autonomous mobile robot converts the distance of the measured image displacement to the actual distance and indicates the actual distance.
Simply, when the autonomous mobile robot moves, the autonomous mobile robot captures images of the floor space at a predetermined time interval, compares the current image with the previous image, measures the displacement between the two images, converts the measured displacement to the actual, distance, and evaluates its actual travel distance. This method is simply limited to obstacle identification and travel distance calculation by movement of the autonomous mobile robot, but the method does not take a more effective shortest travel distance to the destination into consideration.
Recently, the autonomous mobile robot has been applied to a home automation system, and thus the autonomous mobile robot is developed to execute a specific function (e.g., cleaning or security). Further, the autonomous mobile robot is connected to a home server that manages and controls a home network system in the home and which is developed to execute various functions. Further still, the autonomous mobile robot is developed to an artificial intelligence robot that may provide required results corresponding to circumstances of a user through interactivity with the user or a mobile terminal of the user.
Therefore, the autonomous mobile robot should be located sufficiently near the user such that the user can demand necessary operations to the autonomous mobile robot in a dialogic manner. Thus, the autonomous mobile robot should find the location of the user and travel to a target point where the user is located. Conventionally, however, a technique for finding the location of the user and traveling the shortest distance to the location where the user is located, is not suggested for the autonomous mobile robot.